The present invention is directed to making folded leaflets which have panels thereof glued or otherwise adhered together to form a closed leaflet which, in some instances, is called an "outsert" if the leaflet contains instructional directions for the use of a pharmaceutical product with which the leaflet is packaged and, in other instances, is merely called a "leaflet" when, for example, the leaflet is used in the food industry.
The present invention will be described hereinafter in connection with its preferred use which is to provide instructions for the making of a food product from the material such as a dessert gelatin. While high speed operations are generally used to dispense outserts in a packaging operation for the pharmaceutical industries, even higher speeds of operation are needed to dispense closed folded leaflets in a packaging operation in the food industries in which leaflets should be dispensed and packaged at speeds of 20,000 to 36,000 per hour.
In forming closed leaflets for later dispensing at such speeds, it is important that the loose edges or loose panels of the leaflets be directed downstream of the traveling folded sheet so as not to catch air and lift or flutter and cause jamming of the equipment. Further, the completed closed leaflet preferably is formed with all of the loose panels or loose edges on the inside of the leaflet and with only folded edges all the way around the outside of the leaflet to prevent air from catching and lifting a single panel when the leaflet is fed at high speeds to and through the packaging equipment. Thus, the preferred leaflet has a double sheet thickness on the outside and folded edges all around with the outer sheet panel being held down by the inner sheet panel to which it is joined at the folded edges. The method and apparatus herein disclosed is directed not only to a folding design which can be achieved at very high speeds but also a gluing design whereby the panels may be glued together to form the completed closed leaflet useable with high speed packaging equipment.
One previously known attempt to glue folded leaflets included in the step of cutting a hole in an interior middle folded section of the leaflet and applying glue to an outer adjacent section at the hole location so that the glue could project through the hole to be adhered to a folded section on the other side of the middle panel. Manifestly, the cutting of holes in the sheets is an operation to be avoided and the leaflet, when unfolded, is marred by unsightly holes. Other closed leaflets have been formed but at low speeds or with configurations that do not permit their subsequent feeding at very high speeds in high speed packaging equipment. Thus, there is a need for a commercial method and apparatus for folding and gluing folded sheets at high speeds of 400 to 600 per minute and, in a folded adhered leaflet of a design, that can be subsequently packaged at similar speeds. To be commercially acceptable, the apparatus should be relatively trouble-free and capable of operating for long periods of time with little down time for maintenance or clearance of jamming of paper in the apparatus.
Accordingly, a general object of the invention is to provide a new and improved folded leaflet of the above-described kind. Another object of the invention to provide high speed method and apparatus for folding and gluing leaflets having first folds in a first direction and cross folds extending normal to the first folds to form a complete closed leaflet preferably with closed edges entirely around the outside of the leaflet. These and other objects and advantages of the present invention will become apparent from the following detailed description taken in conjunction with the accompanied drawings in which